The manufacture of α,β-unsaturated ketones and alcohols from bicyclic compounds is described in GB Patent No 1,300,970. The process described therein consists of the reaction between a tetra-substituted unsaturated bicyclic compound with a hexavalent chromium compound (e.g. Na2Cr2O7) in the presence of short-chain-alkanoic acids as acidic vehicles (e.g. acetic acid), which results in a carbonyl (e.g. ketone) or carbinol (e.g. alcohol) containing product. Another method for manufacturing α,β-unsaturated ketones and alcohols from bicyclic compounds is described in DE U.S. Pat. No. 2,220,820. In that method, cobalt and/or copper salts (e.g. cobalt (II) naphthenate and copper (II) acetate) are claimed as catalysts.
A particular application of the above conventional methods results in unsatisfactory activity and selectivity as considerable amounts of undesirable alcohols are produced along with the desirable ketone, namely 1,2,3,5,6,7-hexahydro-1,1,2,3,3-pentamethyl-4H-inden-4-one (c.a. 60 weight % conversion and <30 weight % yield to ketone). These substances have strong, persistent, musk woody odours with various rich amber, precious woody, or fine woody overtones. Therefore, the manufacture of said indenones provides novel perfume and fragrance compositions.
The object of the present invention is to provide a method for allylic catalytic oxidations to obtain α,β-unsaturated ketones and alcohols from bicyclic compounds with oxygen and catalysts comprising metal-organic compounds and a solid catalyst based on gold that favours conversion and selectivity.